Class Notes (811,043)
Canada (494,456)
York University (33,712)
Natural Science (2,769)
NATS 1840 (165)
all (1)


39 Pages
Unlock Document

York University
Natural Science
NATS 1840

NATS 1840 LECTURE NOTES SEPT. 13, 2011 Environmental Science & Thinking (UNIT 1) Environment - Everything that surrounds you, from just outside your skin to the edge of the universe. - The environment consists of all those parts of the physical world that help to sustain life. o If a part of the environment is under stress (a change), then its ability to sustain life may be threatened. Environmental Science - The study of how the environment works, and of humanity’s impact upon it. o A science o Interdisciplinary (draws upon many varieties of science knowledge) o Both theoretical and applied science (understand the changes that take place and the causes of the change) Science - The systematic study of how and why nature works the way it does. - Uses empirical methods (testing one’s offered explanations) to test possible explanations of observations. - Seeks to uncover basic underlying principles so that predictions may be made. - A rational process drawing upon two forms of reasoning…. o Inductive reasoning – synthesis, creativity, inspiration and imagination o Deductive reasoning – logic, self-consistency, rigour, mathematics Induction: Reasoning Based on Experience - The mode of thinking used in the formation of a hypothesis - General conclusion from limited number of observations - Synthesis of many observations - Bottom-up approach (starts with observations) - Limited by finite number of observations – not logically valid. o Inductive conclusions can only be “proved” in the sense that they are very likely, but not guaranteed, to be true. - Ex. All objects ever observed fall to the ground when dropped. Therefore, all objects fall to the ground. Deduction: Logical Reasoning - Crucial in analyzing the consequences of a hypothesis - Specific conclusions drawn logically from a generalization. - Conclusions are reliable, at least internally. - A top-down approach. - Limited by quality of assumptions o Deductive conclusion only as good as its premises o Although logically valid, any deductive conclusion based on incorrect premises is invalid The Scientific Method - Based mainly on inductive reasoning and observations - Deductive reasoning crucial for designing tests (usually called experiments) o Observation(s) o Question(s) o Hypothesis o Test hypothesis…do an experiment o Critically evaluate the results of the test o Determine if hypothesis is supported or contradicted o Disseminate (5) and (6), usually in a refereed (peer reviewed) publication - Hypothesis disproved: question still remains - Hypothesis supported: deductive consequences of that hypothesis must be tested. What is a good scientific statement? - A hypothesis must be falsifiable (can be disproved), at least in principle. Examples: o The moon is made of cheese o Cell phones cause brain cancer o Sun’s energy source is nuclear fusion - A hypothesis that can’t be falsified (is untestable) isn’t a scientific statement o God & Afterlife o Before the Big Bang o Some ‘conspiracy theories’- example UFO The Hierarchy of Scientific Statements - Hypothesis o Tentative answer to a question, i.e. an assumption o Weakest scientific statement - Theory o (based on inductive ideas) (experiments are made through deductive reasoning) o A hypothesis, or set of hypotheses, that has survived many tests o More robust than a hypothesis, in that there is greater confidence that it is right - Law o A theory that has passed so many tests that it is considered a fact o Observation seen so often that it becomes a fact o Most robust of all scientific statements Scientific Experiments - To be a useful test of a hypothesis, can experiment must be o Controlled o Statistically significant o Repeatable - Absence of one or more of these criteria means a flawed experiment whose results shouldn’t be trusted until they have been reproduced by a reliable experiment. Controlled experiments - Many variables may influence the outcome of an experiment - Outcome of a controlled experiment depends on only one variable. Control Group Subject Group Common Experiment Group 1 (many variables) Group 2 Act on one variable Observe Responses Group 1 Group 2 - Any difference in response between subject and control must be due to the single different variable. NATS 1840 LECTURE NOTES SEPT 15, 2011 Environment Science & Thinking (UNIT 1) Statistical Significance & Scientific (Un)certainty - The outcome of any measurement is characterized by o Accuracy  how close the outcome if to the ‘true’ value o Precision  the degree to which repeated measurements yield the same value - Uncertainty in a measurement describes the range within which the ‘true’ value most likely lies o For instruments (ruler, thermometer….) uncertainty is one half of the smallest division on the scale. o Uncertainty in the average of several measurements decreases with the number of measurements in sample. N = 10 (uncertainty =31%) N = 100 (uncertainty = 10%) Statistical Significance - Controlled experiment with N1 and N2 controls (or measurements). Averages differ and have some uncertainty. - Is the difference real? Or just the result of random choice? o To be statistically significant the difference in the averages must be greater than the error ranges. - Random fluctuations might mimic a real response in a controlled experiment. Statistical significance ensured by o Conducting experiment with many subjects and controls o Repeating several times Repeatability - An experiment should be describable in sufficient detail to allow any independent replication to yield the same outcome. This helps to reduce: o Uncertainties o Mistakes o Bias - Detailed notes must be kept at each step - Repeatability argues against ‘proprietary’ or ‘trade’ secrets, and in favour of full disclosure of date and methods. NATS 1840 LECTURE NOTES SEPT 20, 2011 Environment Science & Thinking (UNIT 1) Junk Science - Term reserved for results that are presented as scientifically valid, but fail to conform to normal scientific standards and/or are only partially true. o Can be motivated by ego, greed, etc. - Problems typically include o Selectivity  results picked to support a priori favoured view. o Distortion of conclusions (eg. “it is possible…” becomes “it is confirmed…”) o No peer review o Publication in places of questionable repute Detecting Junk Science - Reliability of unexpected/extraordinary claims may be gauged by asking questions such as: o Are the sources reliable? o Do they have an ulterior agenda? o Have the results been verified (reproduced) by others? o Does the result represent the majority view among scientists? o Does it make sense? o Is previous knowledge accommodated? o Is the presentation balanced? Are criticisms addressed? o What were the sources of funding? o Has there been peer review? - Multiple ‘negative’ answers might be an indicator of junk, but not necessarily so. - Caution! Less clear at the frontiers of knowledge. Consensus might change rapidly. Pseudoscience (Pseudo = False) - Knowledge presented as if it has a scientific foundation, even though it does not o Includes astrology, creation science/intelligent design. - Quality of any results obtained is irrelevant - Typically, o Isn’t self-correcting; o Doesn’t establish theoretical underpinning; o Dismisses skepticism as narrow-mindedness. NATS 1840 LECTURE NOTES SEPT 20, 2011 Environmental Decision Making (Unit 2) What kind of decisions? - Any decision likely to have some impact on the environment o Problem prevention; o Problem remediation; o Evaluation of alternatives; o Policy direction o Regulation - Often more challenging then it might appear because of the need to weigh many competing factors. What influences decision-making? - Science underpins the decision-making process. But decisions are also informed by: o One’s environmental worldview o Risks relative to likely benefits o Associated costs - Risk and costs can be quantified objectively, but worldviews and the perception of risk are both highly subjective. Environmental Worldview - An individual’s beliefs about o How the world works; o Their role in the world; o Right and wrong environmental behaviour - Reflects the value one places on Nature - Instrumental (Utilitarian) value: o Something is useful to us - Intrinsic value o Something has value by its mere existence NATS 1840 LECTURE NOTES SEPT 22, 2011 Environmental Decision Making (Unit 2) Anthropocentric (human-centered) worldview - Humans have intrinsic value - Nature has utilitarian value - Humans are in charge of the Earth and can act as masters and/or caretakers of the environment Biocentric (life-centered) worldview - All living creatures have intrinsic value - The non-living environmental has utilitarian value - Humans should aim to preserve Nature’s life-sustaining abilities Ecocentric (Earth-centered) worldview - Entire environment has intrinsic value - Humans have no special claim on the environment - Humans are just one of millions of interdependent species - Ecosystems must be protected in their entirety - Humans must adjust their needs to ensure a sustainable future Example: Neo-Malthusians (Ecocentric) - Human population is too high already; - Present resource use & growth is unsustainable; - Pollution should be prevented rather than remedied; - Best technology is small & decentralized - Thomas Malthus predicted (-1800) that mass starvation would soon visit humanity Example: Cornucopians (Anthropocentric) - Increased population means more in genuity; - Ability to Earth to support growth is unlimited; - Economic growth leads to technological advances, less pollution & improved health; - Consequences of pollution to be addressed as needed, provided growth not impeded; - Large, centralized technological solutions - Earth as the horn of plenty What is your own worldview? - Wide spectrum of views and philosophies o Most will disagree with at least some of the ideas at either extreme o Worldviews should be founded upon some knowledge of the fundamental issues o New information available on a regular basis, so outlook should be flexible Risk - The possibility of suffering harm or loss - Everyday risks  instinct - When instinct is insufficient, rely on experience and best estimates to assess risk objectively o Scientific evidence and plausible assumptions used to estimate the probability of harm - RISK = PROBABILITY – LIKELIHOOD OF AN OUTCOME Probability (an example) - Consider a tree with four applies on it, two of which are ripe. - Pick two applies with eyes closed. Q: What is the most likely number of ripe apples in your hands? - Suppose ALL apples are picked. Two are guaranteed to be ripe. So, probability of having one ripe apple after one pick is 50% (or 0.5). o When two applies are picked the number of ripe apples is most likely to be 2 × 0.5 = 1. (But not guaranteed since a given attempt may yield zero or two ripe apples). - Known facts about apples on tree used to estimate probability Example: “There is a 10% probability of rain today.” - Means: 10 out 100 times that the state of the atmosphere is like that presently existing, it rains. (Based on experience) - Suppose the atmosphere is like this 20 times in one year. How many times is it likely to rain? o Answer: 20 days × 10% = 2 days of rain Example: You are 10 times more likely to die from cancer as a result of smoking than from consuming alcohol. - Means: Ten times more cancer deaths can be attributed to smoking as compared to alcohol. (Based on experience) Estimating Risk - Partly the job of science to obtain the data needed to estimate probabilities o Dose-response curves from laboratory data o Real-world failure/accident rates - But what is there isn’t enough data? (ex. no recorded deaths or injuries) - Probabilities of possible scenarios leading to harm. (Subject to continual refinement as new information is uncovered) - Most challenging in situations where a significant lag exists between cause (exposure) and effect Total Risk - Combination of two factors o The probability of harm o The probability of exposure - Multiplied together to yield the actual risk to an individual or community - Example: Suppose graphs show LD50 instead of ED50 o Dose-response = prob (death) is 50% at LD50 o If exposure at LD50 level has a probability of 5%, total risk of death is 0.5 × 0.5 = 0.025 (2.5%) NATS 1840 LECTURE NOTES SEPT 27, 2011 Environmental Decision Making (Unit 2) Perception of Risk - Often different from the objective risk. Reasons are mainly psychological. o We accept greater risk, if taken voluntarily o We underestimate risks associated with familiar activities and overestimate those of unfamiliar ones. o When consequences of something going wrong, are major, associated activity perceived as riskier. o If persons, “in charge” of the risk are decreased trustworthy, risk is perceived to be lower. o If activity gets lots of media coverage, seen as riskier. - Decision makers must reconcile perception with reality, if their conclusions are to be rational. Costs - Often, assessing economic costs means performing a costs benefit analysis o Identify possible impacts and their likelihood; o Evaluate expected value/cost of each o Compare value of the positive impacts to costs of negative impacts Inputs Process Product (Internal costs) (Benefits) Inputs (Internal costs) Difficult to assign economic value to intangibles (beauty, cleanliness,…) and externalities. Externality - Cost borne by persons other than those reaping the benefit. Often overlooked, leading to “The Tragedy of the Commons.” - Value of intangibles & externalities, very difficult to assess objectively. o Some suggest inclusions in price of goods, allowing market forces to resolve environmental problems – controversial o How to implement if no agreement on external costs? - If external costs are unquantifiable or ignored, is an economically rational choice possible? Cost benefit analysis - Cost benefit analysis remains a controversial way to settle environmental issues and shouldn’t be the sole basis of the decision. But it is a place to start. - Ultimately, objective information about risk, costs, and benefits is interpreted through the filter of your worldview, so even with good science a spectrum if to be expected. Decision Making – An Example (Hocking Article) Paper vs. Styrofoam? - 1990, McDonald’s stops using polystyrene packaging. Most other food chains, soon follow. It is now rare to find a Styrofoam cup in a coffee shop. - Public perception -> polystyrene is environmentally bad o Doesn’t decompose in landfill o Ozone-destroying chemicals omitted during productions - Paper cups and packaging seen as environmentally friendly. Are they? - What if all factors are considered? (Hocking, 1991) - Polystyrene involve CFC which is environmentally bad and when dumped they will last long. Life Cycle Assessment: Step 1  Inventory Analysis FACTOR 1 PAPER CUP 1 FOAM CUP Raw Materials 6 1 Steam (heat) 12 1 Electricity 36 1 Cooling Water 2 1 Waste Water 200 1 Emissions (by weight) During Production 2.5 1 (Pentane) After Use (Landfill) Methane NONE Recyclability Poor Good Cost 2.5 1 Intangibles Cutting Trees Oil Extracting - (Pentane has no impact on ozone; methane is 50x more potent a greenhouse has than pentane) - So, is Styrofoam really so bad in comparison to paper? Life Cycle Assessment: Step 2  Impact Prioritization - Each inventory factor must be assigned a priority such assignments reflect one’s worldview as well as objective risk analysis - Criteria might include o Geographical scale of impact o Severity of hazard o Degree of exposure o Penalty for being wrong - Only once a complete life-cycle assessment has been done can a rational choice be made. But two individuals might still disagree. NATS 1840 LECTURE NOTES SEPT 29, 2011 The Ecosphere Ecology - The study of the interactions among living things, and between living things and their physical environment - A major part of environmental science Living Things – A Hierarchy: Community BIOSPHERE (Life) Community Community Community  a collection of populations living in one area at one time. Pop. Population Pop. Population  members of a species living in one place. Species  living things that can breed with one another. Organisms of a Species Ecosystem Community Environment The Physical Environment - Can be divided into three broad compartments o The Atmosphere (air) o The Hydrosphere (water) o The Lithosphere (rocks & soil) - Nutrients and energy are continuously exchanged between the three components and the biosphere Ecosystem - Combination of a community and its physical environment, including all interactions between compartments Community Environment - Ecosystems exhibit great complexity in both structure and interactions o Tempering with one small part can easily affect the whole, often unpredictably. Biome (on land) - Collection of similar ecosystems o Often in one geographical area o Characterized by common climate & similar forms of life o A major ecosystem BIOME Ecosystem Ecosystem Ecosystem Similar climate  long-term weather conditions Similar life forms  well-adopted to the climate Major Terrestrial Biomes: Tundra - Very low average rainfall - Very low average temperature - Treeless - Dominant plants: small shrubs, grasses, mosses & lichens - Comparatively low biodiversity Major Terrestrial Biomes: Taiga (Boreal Forest) - Low average rainfall - Low average temperature - Dense forests - About 20 species of conifers (cone-bearing evergreens) dominate much of this biome Major Terrestrial Biomes: Temperate Forests - Moderate rainfall - Moderate temperature - Trees drop their leaves each season (deciduous) - Deep shade limits animal life to small mammals Major Terrestrial Biomes: Temperate Grasslands - Low rainfall - Moderate temperature - Tall grasses and small shrubs dominate - Greatest variety of large mammals Major Terrestrial Biomes: Tropical Rainforest - Very high rainfall - Very high temperature - Enormous diversity of plants and animals Biome (in the water) - Characterized by four factors o The depth to which sunlight penetrates o The temperature of the water o The nature of the bottom substrate (the stuff at the bottom of the body of water) o The amount of dissolved salts (salinity) - Based on salinity alone we have o Freshwater ecosystems (lakes, rivers, etc.) o Marine ecosystems (Oceans) o Transitional zones (Coastal wet lands) The Ecosphere BIOME BIOME BIOME ECOSPHERE BIOME BIOME - All life on Earth and its environment - A small part of the planet, but the only part that sustains life NATS 1840 TEST # 1 OCT 4, 2011 NATS 1840 FALL ASSIGNMENT OCT 6, 2011 NATS 1840 LECTURE NOTES OCT 18, 2011 Scientific Notation Scientific Notation - For very small or very large quantities, the usual way of writing numbers becomes awkward. - The more compact way of writing very large or very small numbers is called scientific notation. Based on powers of ten. o Given some integer ‘n’, 10 = 10 × 10 × 10 × …. × 10 a total of n times. If n is less than zero, n then 10 = 1/10 × 1/10 × 1/10 × …. ×1/10 n times. - E.g. 74, 000, 000, 000 = 74 × 10 9 1. Count the number of zeros to set the exponent 2. Multiply by the remaining number 3. If less than 1 then change the sign of the exponent - E.g. 0.00000000034 = 3.4 × 10 -10 0 - Note: 10 = 1 3 4 a) Addition (or subtraction)  (2 × 10 ) + (7.4 × 10 ) = (2 × 10 ) + (74 × 10 ) 3 4 = 76 × 10 = 7.6 × 10 b) Multiplication  (2 × 10 ) × (7.4 × 10 ) 3 4 = (2 × 7.4) × 10 × 10 = 14.8 × 10 7 8 = 1.48 × 10 Metric (SI) Prefixes: - When measurements yield very mall of very large quantities it is preferable to express the result in terms of the ‘natural’ scale of the situation 3 6 - E.g. 10 metres = 1 kilometre = 10 millimetres Biogeochemical Cycles: The Cycling of Matter & Energy in the Environment Preamble: - Living organisms consume nutrients and energy to thrive o Six “macronutrients” are constantly recycled – carbon, oxygen, hydrogen, nitrogen, phosphorus, and sulphur - Biogeochemical cycles: physical and chemical processes which ensure the exchange of matter & energy between the biotic and abiotic parts of the ecosphere. - To understand these cycles, we must understand the nature of matter and energy Biogeochemical Cycles Part I – Matter - Matter: anything that takes up space and has mass. o Composed of atoms of elements which interact chemically with one another to form more complicated molecules of compounds. - Elements: basic chemical constituents of matter, i.e. the stuff from which all things are made. o Each element has distinct physical properties o Elements cannot be further broken down by chemical means. - Atom: basic physical unit of an element, i.e. smallest piece of matter that exhibits the properties of that element o The physical characteristics of an atom determine the properties of the corresponding element. - Atoms themselves are composed of tiny sub-atomic particles: o Electrons, protons, neutrons  the basic constituents of all atoms. - Structure of an atom: Small, dense nucleus of protons and neutrons, surrounded by large, diffuse cloud of electrons. o Size: about 10 -1m - Each sub-atomic particle carries a specific electric charge. The electromagnetic force acts between charged particles, exerting a force which depends on the charges involved. o Two positively –charged (+,+), or two negatively –charged (-,-) particles repel each other o Two oppositely-charged (+,-) particles attract one another o Particles that are electrically neutral (carry on charge) do not experience this force.  Protons (+) positive charge  Neutrons (0) neutral charge  Electrons (-) negative charge Identity of Atoms: - What gives an atom its particular chemical properties (and determines which elements it corresponds to)? 1. Overall electric charge of the atom 2. Nuclear charge ( = # of protons): Atomic Number 3. Nuclear mass ( = # of protons + # of neutrons): Mass Number - Atomic number uniquely determines the chemistry of an atom (and the element involved) - Atoms with different mass numbers but the same atomic number are called isotopes of that element. Isotopes of an element differ mainly in their nuclear properties. - Chemical Notation o E.g. the element with atomic # = 6 => called Carbon, symbol C  Explicitly… • 6C6= C =12put the atomic number on the left of the symbol (6), put # of neutrons on the right, and the mass # is always above the symbol (C). Anything in the right hand corner indicates the number of extra electrons. NATS 1840 LECTURE NOTES OCT 20, 2011 Biogeochemical Cycles (Con’t) Noble gases => ‘Closed Shells” Halogens (F, Cl…) - One electron of a closed shell - Want extra electron Alcali Metals (Li, Na, K…) - Have one extra electron above closed shell - Want to get rid of it Molecules and Compounds: - Compound: substance consisting of two or more elements whose chemical properties are distinct from those of its constituent elements - Molecule: Two or more atoms bound to one another. o Can involve atoms of the same element, yielding the molecular form of that element, OR o If the atoms involved are of two different elements, then the molecule is the fundamental unit of a compound o Molecules are to compounds as atoms are to elements Identity of Molecules: - Identities by names and quantities of their constituent atoms, as well as any net charge. Eg. “carbon dioxide” means one atom of carbon and two atoms of oxygen, i.e. CO 2 - Environmentally important molecules include: o Molecular Hydrogen – H 2 o Molecular Oxygen – O 2 o Molecular Nitrogen – N 2 o Water (dihydrogen oxide) – H O 2 o Carbon dioxide – CO 2 o Ozone – O 3 o Methane – CH 4 o Nitogen Dioxide – NO 2 o Ammonia – NH 3 - Organic compound: involves chains or rings of carbon atoms - Carbohydrates: contain mostly carbon, hydrogen, & oxygen. Eg. glucose = C H O 6 12 6 Reactions: - Processes in which nuclei, atoms, or molecules interact in a manner which changes how they are bound Ingredients Products Reaction - If products are more tightly bound overall compared to the ingredients, reaction is exothermic – energy is released (from the ingredients) in the reaction. - If products are less tightly bound than the ingredients, reaction is endothermic – energy must be added to the ingredients for the reaction to occur. Chemical Reactions: - Only atoms and molecules undergo chemical reactions. Only the electron clouds participate – nuclei are unaffected and remain intact. As a result, two important rules apply to chemical reactions: 1. Nuclei are conserved. So, the number of atoms of each element remains the same through a chemical reaction 2. The total charge remains the same through the reaction - Example: Consider burning methane (natural gas) in air: o Methane = CH 2 o Burning (or combustion) means combining with oxygen (O ) 2 o CH 4 O 2CO + H20 + 2eat + Light => reaction cannot happen as written (chemically cannot occur) o CH 4 2O  2O + 22 0 + H2at + Light => each side must equal to each other (chemically can occur) Nuclear Reactions: - Only the protons and neutrons of the nucleus are involved. They can either be re-arranged or transformed. 1. Fission reaction: A heavy nucleus breaks apart into two or more lighter pieces 2. Fusion reaction: Two or more light nuclei bind together to form a heavier nucleus 3. Decay reaction: A small piece of a nucleus breaks off; or a neutron turns into a proton; or a proton turns into a neutron - In a nuclear reaction, the sum of the number of protons and neutrons are unchanged. But, because the number of protons can change the elements involved change Two Ecologically Important Chemical Reactions: - Photosynthesis & Respiration o Chemical reactions which serve to move nutrients and energy through an ecosystem - Photosynthesis is an endothermic reaction o Energy (light from sun) +6H O 2water from hydrosphere) + 6CO (Carbo2 dioxide from atmosphere)  C H 0 (glucose stores energy) + 60 (waste by-product ‘oxygen’) + Energy 6 126 2 - Aerobic Respiration is an exothermic reaction o C6H 12(6lucose) +6O (oxy2en from atmosphere)  6H 0 (waste 2ater) + 6CO (waste carb2n dioxide) + Energy (useful energy plus waste heat) - Respiration is how energy stored in food is released for biological work by oxygen-breathing organisms. All living things respire. NATS 1840 LECTURE NOTES OCT 25, 2011 REFWORKS - Rwyorku  Group code Chemistry Practice - Number on top left corner is Atomic mass/Mass number - Number on top right corner is electron gain/loss - Number on bottom right is neutrons - Number on bottom left corner is protons 1. 207  207 Atomic Mass ? Pb125 125 neutrons  82 protons (207-125) 2. C3H8 + O2  4H2O + 3CO2 + heat  BALANCED  C3H8 + 5O2  4H2O + 3CO2 3. Fe + O2 + H2O  Fe2O3(H2O)  BALANCED  4Fe + 3O2 + 2H2O  2Fe2O3(H2O) NATS 1840 LECTURE NOTES OCT 27, 2011 Biogeochemical Cycles – Part II – Energy Work: - Work is done when matter moves (or changes its state of motion) as a result of the application of a force upon it. Energy: - The ability of a system to move matter through some distance. i.e. the ability to do mechanical work. Power: - Rate at which energy is consumed or received or delivered. - Power = Energy/Time Forms of Energy: - Some are closely associated with tangible physical objects, such as atoms. Other forms, such as the energy carried by light, are less tangible. - We will be mainly concerned with o Kinetic Energy o Potential and Internal Energy o Thermal Energy o Electromagnetic Energy Kinetic Energy - Associated with motion. A moving object has the ability to do work (e.g. in a collision) - Intuitively, a faster object can do more work than a slow-moving object, and a more massive object can do more than a light object. Kinetic energy increases with speed and mass. Potential Energy - Represents the ability to do work stored in a physical system that is not in motion. o Height above ground (gravity) o Bending/stretching of a solid object (elasticity) o Electric charge difference between objects (electricity) o Binding of two or more atoms (chemical energy) - Often the result of mechanical work done against a force at some prior time. Thermal Energy - Kinetic energy associated with the random motion of the molecules making up a substance. Also known as heat. - Temperature is a measure of the average kinetic energy per molecule in a system. - E = 3/2 × k × T o Temp is in °K o 0 °C = 273 °K o k = 1.38 × 10-2J/K More thermal kinetic energy Faster moving molecules Hotter object Thermal Energy Transfer (Conduction) - A fast-moving molecule in a hot object collides with slower-moving molecule in a cooler one. Collision transfer kinetic energy to the slow molecule, and this thermal energy to the cold object. - Thermal energy flows from hot to cold until both objects share the available thermal energy equally. No further net energy transfer between the objects. A steady state is reached – both objects have the same temperature. Thermal HOT COLD Energy Electromagnetic Energy - Vibrating electric charge causes ripples in the surrounding electromagnetic (E.M.) field o Creates a E.M. wave which propagates away from the v
More Less

Related notes for NATS 1840

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.